There are a number of obvious differences between Git and GitHub.
Git itself is really focused on the essential tasks of version control. It maintains a commit history, it allows you to reverse changes through reset and revert commands, and it allows you to share code with other developers through push and pull commands. I think those are the essential features every developer wants from a DVCS tool.
No Scope Creep with Git
But one thing about Git is that it is really just laser focused on source code control and nothing else. That's awesome, but it also means the tool lacks many features organizations want. For example, there is no built-in user management facilities to authenticate who is connecting and committing code. Integration with things like Jira or Jenkins are left up to developers to figure out through things like hooks. Basically, there are a load of places where features could be integrated. That's where organizations like GitHub and GitLab come in.
Additional GitHub Features
GitHub's primary 'value-add' is that it provides a cloud based platform for Git. That in itself is awesome. On top of that, GitHub also offers:
- simple task tracking
- a GitHub desktop app
- online file editing
- branch protection rules
- pull request features
- organizational tools
- interaction limits for hotheads
- emoji support!!! :octocat: :+1:
So GitHub really adds polish and refinement to an already popular DVCS tool.
Git and GitHub competitors
Sometimes when it comes to differentiating between Git and GitHub, I think it's good to look at who they compete against. Git competes on a plane with tools like Mercurial, Subversion and RTC, whereas GitHub is more in the SaaS space competing against cloud vendors such as GitLab and Atlassian's BitBucket.
No GitHub Required
One thing I always like to remind people of is that you don't need GitHub or GitLab or BitBucket to use Git. Git was released in what, 2005? GitHub didn't come on the scene until 2007 or 2008, so big organizations were doing distributed version control with Git long before the cloud hosting vendors came along. So Git is just fine on its own. It doesn't need a cloud hosting service to be effective. But at the same time, having a PaaS provider certainly doesn't hurt.
Working with GitHub Desktop
By the way, you mentioned the mismatch between the repositories in your GitHub account and the repos you have locally? That's understandable. Until you've connected and done a pull or a fetch, the local Git repo doesn't know about the remote GitHub repo. Having said that, GitHub provides a tool known as the GitHub desktop that allows you to connect to GitHub from a desktop client and easily load local Git repos to GitHub, or bring GitHub repos onto your local machine.
I'm not overly impressed by the tool, as once you know Git, these things aren't that hard to do in the Bash shell, but it's an option.